6 "old" CPUs worth buying in 2026 because they work with the RAM you already own

Published Oct 6, 2026, 4:30 PM EDT After a 7-year corporate stint, Tanveer found his love for writing and tech too much to resist. An MBA in Marketing and the owner of a PC building business, he writes on PC hardware, technology, and Windows. When not scouring the web for ideas, he can be found building PCs, watching anime, or playing Smash Karts on his RTX 3080 (sigh). It's no secret that the last 12 months have been terrible for buying PC hardware. From RAM and SSDs to graphics cards, everything has reached record prices, thanks to the global silicon shortage. CPUs, however, haven't seen major price hikes, which remains a silver lining for those looking for an upgrade. However, the total platform cost that comes with it has spoiled the party for DDR5 enthusiasts. Those of you already using a previous-gen, DDR4-based system can instead look toward AM4 and LGA 1700 processors. These CPUs are compatible with the DDR4 RAM you already have in your rig, and they aren't bad buys by any definition. At the right price, whether brand-new or pre-owned, these "old" CPUs can be great drop-in upgrades for both modern gaming and productivity. Ryzen 7 5800X3D: The fastest AM4 gaming chip No holds barred The recently relaunched Ryzen 7 5800X3D remains both iconic and powerful even in 2026. The first chip to truly show the potential of AMD's 3D V-Cache, the Ryzen 7 5800X3D still trades blows with modern 6-core chips from Team Red. Despite chips like the Ryzen 7 7800X3D and 9800X3D handily beating it in gaming performance, the Ryzen 7 5800X3D is still a decent pick for AM4 users. If you're switching from any Ryzen 1000, 2000, or 3000 CPU, then the Ryzen 7 5800X3D will deliver a massive boost to your framerates. Most AM4 motherboards can support this chip with a BIOS update, allowing you to upgrade your PC without paying for a new motherboard and RAM kit. The only caveat is the price. The Ryzen 7 5800X3D has shot up on the used market with listings exceeding $400. Instead, a brand-new 10th-anniversary edition of the Ryzen 7 5800X3D can be bought for around $350 on multiple ecommerce platforms (at the time of writing). It's not a small investment, especially on a dead platform, but it's certainly cheaper than a full platform upgrade, which probably won't outperform the Ryzen 7 5800X3D anyway. AMD Ryzen 7 5800X3D Cores 8 Threads 16 Socket AM4 Base Clock Speed 3.4 GHz Boost Clock Speed 4.5 GHz Cache 100 MB AMD's Ryzen 7 5800X3D is the company's first gaming CPU with 3D V-Cache, which adds a ton of L3 cache for even better gaming performance. It's on the older AM4 platform, but is still a potent gaming chip. Ryzen 9 5900X: The productivity pick AM4 isn't just for gaming This 12-core, 24-thread processor is 6 years old at this point, but that doesn't mean it's automatically outdated. If gaming isn't your primary concern, the Ryzen 9 5900X should be on your radar, especially if you want to save a few bucks. This workstation chip still packs a punch in productivity workloads, and is obviously no slouch in gaming either. While it launched at $550 in 2020, you can find it on eBay for around $250 today. That's a steal for a CPU of this caliber, and it can last you for a while. The upgraded model, i.e., the 16-core, 32-thread Ryzen 9 5900XT, is regularly available for around $300 if you want something even more powerful. AMD Ryzen 9 5900XT Ryzen 7 5700X: The budget upgrade Ideal for most gamers For those of you who want an affordable upgrade over your existing AM4 chip, the Ryzen 7 5700X is undoubtedly one of the best options. I've been using this chip for over four years now, and it hasn't let me down. I've paired it with the RTX 3080, and it has allowed me to enjoy the latest AAA games at smooth framerates at 1440p. This 8-core, 16-thread CPU has a meager 65W TDP despite being a decent productivity chip. Using PBO, you can extract the most out of it, and I've been able to overclock it for some extra juice, too. Its gaming performance is almost identical to that of the Ryzen 5 5600X, but it's possible to buy it at the same price, too. If the difference is significant, then I'd advise going for the 6-core chip. Used models are currently a no-go for the Ryzen 7 5700X, since they cost as much as buying it new on Amazon. AMD Ryzen 7 5700X The AMD Ryzen 7 5700X is an excellent processor with 8 Cores and 16 processing threads that provide plenty of power and speed. Ryzen 5 5600X3D: 3D V-Cache on the cheap 6-core gaming doesn't have to be lackluster You don't need the Ryzen 7 5800X3D to enjoy AMD's 3D V-Cache in your games. The significantly cheaper Ryzen 5 5600X3D provides virtually the same performance as the Ryzen 7 5700X3D, and sits just below the Ryzen 7 5800X3D. If you want a gaming-focused chip without spending over $300, the Ryzen 5 5600X3D can be had for just $220 (at the time of writing). It's relatively harder to find, but you can try your luck on Micro Center and Amazon. AMD Ryzen 5 5600X3D Core i5-12400F: The budget pick for Intel users If you wish to join Team Blue Intel's 13th and 14th Gen processors were mired in controversy due to an infamous bug causing high voltages, which dealt lasting damage to the silicon. The older 12th Gen chips, however, were Intel's comeback as Alder Lake showed what a hybrid core architecture could do. The Core i5-12400F was one of the best gaming CPUs when it launched, and 4 years later, it's certainly not old. The 6-core, 12-thread CPU (no E-cores) is as fast as the Ryzen 5 5600X in gaming, and costs the same on the used market ($125–$150). It's a starter 12th Gen chip, so it only makes sense for those building a budget PC from scratch. This means buying a cheap LGA 1700 DDR4 motherboard and 16GB/32GB of RAM, but at least you won't have to shell out a small fortune for DDR5 memory. And you have the option of swapping your motherboard for a DDR5 model while retaining the CPU. Core i7-12700KF: When you need more horsepower The one for productivity fans Credit: Wikimedia Commons The Core i7-12700KF is a 12-core workhorse on the same LGA 1700 platform, providing capable multithread performance while slightly beating chips like the Ryzen 9 5900X. Whether it's gaming or productivity you want on an Intel system, the Core i7-12700KF won't disappoint. At the time of writing, it's still available brand-new for around $220 on sites like Amazon. This 8 P-core, 4 E-core chip is powerful enough to last you a few more years while you wait for the market to settle down. When it does, you can consider buying a DDR5 motherboard and RAM kit for a sweet performance boost. LGA 1700 is a dead platform, just like AM4, but that doesn't mean it's useless in 2026. Intel Core i7-12700KF $290 $292 Save $2 The Intel Core i7-12700KF is one of the best processors for this job. It's a step above the 12600K and even matches the general performance of 12900K CPU at a relatively affordable price. Make the most of your DDR4 PC It's not the right time to shop for new CPUs that require selling your kidney to afford a DDR5 memory kit. Instead, upgrading to a capable AM4 CPU or building around an LGA 1700 chip can save you money without a massive drop in performance. There's no lack of options on either platform, and those with an already compatible PC need only a good deal on an older CPU to avoid the inflated PC hardware market.